19th International AIDS conference

The 19th International AIDS Conference has just begun in Washington DC. For many years now, this congress has had the feeling of a dug-in battle against a hugely difficult problem. However, there is a sense of excitement this year as more people than ever are being treated with effective medications in developing nations. However some research from Australia evaluates the situation among intravenous drug users in Tanzania as a time bomb.

Transcript

Norman Swan: The 19th International AIDS Conference is on this week in Washington DC. For many years now, this congress has had the feeling of a siege -- a dug-in battle against a hugely difficult problem.

This year’s meeting has a sense of excitement though. More people than ever in developing nations are being treated with effective medications. Mother-to-child transmission is falling in many places and amazingly they are now saying that the load of virus becomes so low when on anti-HIV medications that they can prevent transmission.

Research from Australia being presented at the Congress though reminds us that this is an infection of poorer nations with lots of other factors involved.

Dr Mark Stoove of the Burnet Institute in Melbourne has been evaluating the situation among intravenous drug users in Tanzania and found a time bomb. Mark is the Burnet's principal researcher in sexual and reproductive health.

Mark Stoove: There’s a generalised HIV epidemic in Tanzania as there is in most parts of sub-Saharan Africa and it is largely in mainland Tanzania transmitted through heterosexual contact.

Norman Swan: Which is typical of the rest of Africa or a lot of Africa.

Mark Stoove: Yes and it’s a gendered HIV epidemic so that women are far more infected in terms of transmission than men.

Norman Swan: To what extent?

Mark Stoove: Twice as many infected as men.

Norman Swan: So tell me about the research.

Mark Stoove: The research was conducted by a French non-government organisation Médecins du Monde and we were brought on board as technical advisers in terms of doing the data analysis and technical reporting. They concentrated on drug users in Dar Es Salaam, in particular the poorest district which has a very high and visual presence of drug use and injecting drug use. They’ve just commenced a harm reduction program in Dar Es Salaam and were interested to look at HIV prevalence and other blood borne virus prevalence to inform their prevention programs.

Norman Swan: And what did you find?

Mark Stoove: We found an enormously high level of HIV -- far higher than the background prevalence of HIV in Dar Es Salaam. We found about 30% of males who participated in the study were HIV positive and about 67% of females, which represents about four times the background prevalence for males and about six times the background prevalence for females.

Norman Swan: Before we get to the implications, you also looked at other blood borne diseases.

Mark Stoove: We looked at hepatitis C, the other blood borne virus infection associated with injecting drug use. Now to our knowledge this is the first prevalence estimate for hepatitis C in Tanzania and we found a prevalence of about 28% of injecting drug users being HIV positive who participated in this study, which has significant implications in relation largely to hepatitis C. We don’t think that co-infection with hepatitis C and HIV has much of an effect on HIV disease progression but the reverse is not the case. Being infected with HIV has significant implications for hepatitis C progression. If you are mono-infected with hepatitis C you are talking about disease progression trajectories where you might look at serious liver disease over a 20 or 25 year period. If you are co-infected with HIV you might halve that. So what you’re talking about in a resource poor setting...

Norman Swan: …is a large number of people heading for liver failure.

Mark Stoove: Absolutely -- a very high liver related burden of disease and that has significant implications for a country like Tanzania and indeed other neighbouring countries that have a burgeoning epidemic of injecting drug use.

Norman Swan: Because like HIV you’ve got very effective drugs now for hepatitis C but they cost a fortune.

Mark Stoove: Absolutely, they are very expensive.

Norman Swan: How much did the people know about HIV and hepatitis C?

Mark Stoove: We asked whether they knew what HIV was and 98% could say I know what HIV is and could describe it. But only about 2% of the sample had ever heard of hepatitis C and they were the ones with the testing history. So overwhelmingly people had no idea what hepatitis C was and had never been tested for hepatitis C in the past.

Norman Swan: So what are the implications of this study, not just for Tanzania but for the epidemic in Africa?

Mark Stove: I think there are a number of implications, I think much of the focus on HIV in Africa and East Africa has been around heterosexual transmission.

Norman Swan: And what you’re showing is that there’s this major group of drug users.

Mark Stoove: Absolutely. HIV prevalence has declined or at least stabilised over the last half a decade and that’s largely due to the provision of anti retroviral therapies in resource poor settings. The current paradigm is now very much around treatment as prevention, so it’s around getting as many people tested and diagnosed as early in their infection as possible so that they can go on anti retroviral therapies both for the own health benefits but also to reduce the risk of transmission to others.

Norman Swan: So what you’re saying then is you’ve got this population of IV drug users who could be a potential threat to all that because they’re a reservoir of both hepatitis C and HIV?

Mark Stoove: Absolutely, so what we see is you know the potential for transmission from a very high risk but relatively small population transmitting to the general population. What we found amongst HIV positive injecting drug users was that over half reported unprotected sex in the past month. It was also reasonably common for female drug users to be engaging in commercial sex, so there is a genuine risk within these types of populations for a particular high risk population such as injecting drug users refuelling the epidemic amongst heterosexual populations.

Norman Swan: Is there a growing IV drug using population in Africa in general?

Mark Stoove: There’s very little research across Africa but certainly in East Africa, and part of that has been driven by changing heroin trafficking routes over the years. More heroin is trafficked through East Africa out of Central Asia these days and it’s also processed further up the line. So what researchers found is the availability of white heroin, which a more injectable form, began appearing in East Africa in the late 1990s and that’s largely what's driven the injecting of heroin. Prior to that heroin was available but it was largely smoked.

Norman Swan: What can you do about it, what’s the plan for harm reduction?

Mark Stoove: This study that Médecins du Monde instigated was called a rapid assessment and response. The rapid assessment has occurred in terms of the data collection and very much a part of that is the response. They've commenced a harm reduction program in the district...

Norman Swan: So this is needle distributions, condoms, the sort of things we’ve been doing in Australia for many years.

Mark Stoove: Yes, absolutely, the provision of opioid substitution therapies for those who...

Norman Swan: Methadone clinics.

Mark Stoove: Yes, methadone, and buprenorphine and also, given that three quarters were undiagnosed for HIV, it’s very important to incorporate a voluntary counselling and testing program within harm reduction programs and also make referral to treatment available.

Norman Swan: Dr Mark Stoove of the Burnet Institute in Melbourne, I’m Norman Swan and you’ve been listening to the Health Report here on RN and I’ll see you next week.